Aspeaker fixed to a moving platform moves toward a wall, emitting a steady sound with a frequency of 245 hz. a person on the platform right next to the speaker detects the sound waves reflected off the wall and those emitted by the speaker.

how fast should the platform move, vp, for the person to detect a beat frequency of 3.00 hz?

How does the amount of energy required to hold each proton and neutron in the nucleus compare to the energy released when they are removed?

A3.9 g aluminum foil ball with a charge of +4.1×10−9 c is suspended on a string in a uniform horizontal e⃗ field. the string deviates to the right and makes an angle of 30∘ with the vertical. part a part complete what information about the e⃗ field can you determine for this situation? what information about the field can you determine for this situation? only the magnitude of e⃗ only the direction of e⃗ both the magnitude and the direction of e⃗ none of the above previous answers correct part b determine the magnitude of the electric field. express your answer with the appropriate units. e e = nothing nothing request answer part c determine the direction of the electric field. determine the direction of the electric field. to the right to the left away from you toward you

What is the role of lenses in microscopy?